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Cirrhilabrus brunneus, a new wrasse (Pisces: Labridae) from north-eastern Kalimantan, Indonesia.

Abstract

Cirrhilabrus brunneus is described from a single male specimen, 43.6 mm SL, collected at north-eastern Kalimantan, Indonesia. It is one of only three species in the genus that possesses a lunate caudal fin. The new species, which is overall dark brown in colour, including the median and pelvic fins, closely resembles C. lunatus from the Ryukyu Islands, southern Japan, and the Ogasawara Islands. However, unlike the latter species, it lacks a broad orange-yellow zone along the sides at the level of the pectoral fins, a pale yellowish band along the base of the dorsal fin, and irregular diagonal red lines on the snout and the postorbital portion of the head that extends onto the anterodorsal part of the body. There is also a substantial difference in maximum size with males of C. lunatus attaining a maximum standard length of about 85 mm in comparison with less than 50 mm for C. brunneus.

Keywords

Taxonomy, marine fishes, Cirrhilabrus, new species, Labridae, Kalimantan, Indonesia

Introduction

The labrid genus Cirrhilabrus Temminck and Schlegel contains small, colourful, sexually dimorphic fishes that inhabit Indo-west Pacific coral reefs. Allen (2000) listed 36 species, but since then six additional species have been described by Senou and Hirata (2000), Randall and Pyle (2001), Randall and Nagareda (2002), and Allen et al. (2003).

The members of the genus typically live in rubble habitats, frequently below 20 m, and feed on zooplankton well above the bottom. Due to their relatively deep-dwelling habits, most species remained undetected until the widespread use of scuba equipment by scientific divers over the past few decades. No doubt additional discoveries will occur in the future, especially with the increased use of specialized deep diving equipment such as mixed-gas scuba and small research submarines.

The present paper describes a new species that was collected by the author during a recent coral reef survey for The Nature Conservancy at the Berau district of north-eastern Kalimantan, Indonesia.

Materials and Methods

Counts of fin spines are given in Roman numerals and soft rays in Arabic. Pectoral ray counts include the rudimentary upper ray. The lateral line is interrupted; the count of the anterior part is given first, followed by a plus sign and the peduncular part. Only lateral line scales with tubes are counted. All the tubed scales of the peduncular part are counted, even though one is usually located posteriorly to the base of the caudal fin. The number of scales in the rows on the cheek is counted from where they commence below the front of the orbit to behind the centre of the orbit. Gill raker counts include all rudiments. Because it may be difficult to determine which raker is at the angle, only the total gill raker count is given.

Lengths of specimens are given as standard length (SL) except estimates of total length (TL) of fishes photographed underwater; this is the straight-line measurement from the front of the upper lip to the base of the caudal fin (end of hypural plate). Measurements are given as percentages of the standard length. Head length is the distance from the front of the upper lip to the posterior end of the opercular membrane. Body depth is the greatest depth to the base of the dorsal fin (adjusting for any malformation of the abdomen due to preservation). Body width is measured just posterior to the opercular flap. Snout length is taken from the front of the upper lip to the fleshy edge of the orbit (if the upper jaw is protruded, it is pressed back to the non-protractile position before the measurement is taken. The same is true of SL and head length measurements. Orbit diameter is the greatest fleshy diameter. Interorbital width is the least bony width. Caudal peduncle depth is the least depth; caudal peduncle length is the horizontal measurement between verticals at the rear base of the anal fin and the caudal fin base. Measurements of fin spines and rays are taken to the extreme base of these elements. Caudal concavity is the horizontal distance between the tips of the longest and shortest caudal rays. Pectoral fin length is taken from the tip of the longest ray to the base of this ray. Pelvic fin length is measured from the base of the spine to the tip of the longest ray.

The holotype and only known specimen is deposited at Pusat Penelitian dan Pengembangan Oseanologi, Jakarta, Indonesia (NCIP).

Cirrhilabrus brunneus n. sp. Dusky Wrasse (Fig. 1)

[FIGURE 1 OMITTED]

Holotype: NCIP 6306, male, 43.6 mm, Kaniungan Besar Island, East Kalimantan, Indonesia (01[degrees]06.934'N, 118[degrees]50.127'E), 40 m, collected with quinaldine sulphate and hand net by G. Allen, 20 October 2003.

Diagnosis

Dorsal rays XI,9; anal rays III,9; pectoral rays 15; lateral line scales 17 + 6; median predorsal scales 5; horizontal scale rows on cheek below eye 2; gill rakers 13; body depth 3.1 in SL; head length 2.9 in SL; snout length 3.9 in head; lunate caudal fin of male with produced lobes; pelvic fins relatively short, not reaching anal fin origin when depressed; diagnostic live colour pattern features of males include a dusky brown overall coloration with bronze hue on breast and belly, dark brown median and pelvic fins with broad white posterior margins on dorsal and caudal fins, and dorsal and ventral edges of caudal fin with prominent brown margins that taper to a point posteriorly.

Description

Proportional measurements expressed in thousandths of the standard length are provided in parenthesis in the following paragraphs.

Dorsal rays XI,9; anal rays III,9; dorsal and anal soft rays branched except first and second rays of dorsal fin and first ray of anal fin; the last dorsal and anal soft rays branched to base; pectoral rays 15, the upper two unbranched; pelvic rays I,5; principal caudal rays 13, the upper and lower rays unbranched; upper and lower procurrent caudal rays 4; lateral line 17 + 6; scales above lateral line to origin of dorsal fin 2; scales below lateral line to anus 6; median predorsal scales 5; median preventral scales 5; transverse scale rows on cheek 2, the upper row with 6 and the lower row with 9 scales; circumpeduncular scales 15; gill rakers 13.

Body moderately elongate, the depth 3.1 (32.1) in SL; body compressed, the width 1.9 (16.7) in depth; dorsal profile of head nearly straight, becoming slightly convex on nape; head length 2.9 (33.9) in SL; snout moderately pointed, its length 3.9 (8.7) in head; orbit diameter 3.4 (9.9) in head; interorbital space slightly convex medially, strongly convex laterally, the least bony width 4.4 (7.8) in head; caudal peduncle depth 2.3 (14.7) in head; caudal peduncle length 1.9 (17.7) in head.

Mouth terminal and oblique, forming an angle of about 30 degrees to horizontal axis of body; mouth small, the maxilla just reaching a vertical at posterior nostril, the upper jaw length 4.2 (8.0) in head; dentition of holotype typical of the genus with three pairs of canine teeth anteriorly at side of upper jaw, the first forward projecting, the next two strongly recurved and outcurved, the third much the longest; an irregular row of very small conical teeth medial to upper canines; side of upper jaw with about 16 small conical teeth; lower jaw with a single pair of forward projecting canines and a row of very small conical teeth in the symphyseal gap; side of lower jaw with a row of about 22 small conical teeth, decreasing in size posteriorly. Gill rakers small, the longest on first branchial arch less than half length of longest gill filaments.

Posterior margin of preopercle with 26 fine serrae; margins of posterior and ventral edges of preopercle free to about level of middle of pupil. Anterior nostril small and inconspicuous, in a short membranous tube with a posterior flap, located anterior to upper edge of eye nearly one half distance to front of upper lip; aperture of posterior nostril much larger than any head pores, without elevated rim, located posterior and slightly dorsal to anterior nostril on a vertical with anterior, bony edge of orbit. Pores of cephalic lateralis system adjacent to ventroposterior half of orbit 15; a series of 9 pores along margin of preopercle linking with 4 on mandible to front of chin; a series of 12 pores from above upper edge of preopercle passing dorsal to orbit and ending in front of anterior nostril; a series of 9 pores on each side of head from first lateral line scale to front of scaled part of nape, plus 3 mid-interorbital pores. Scales cycloid; head scaled except snout, interorbital space, and ventrally; lowermost of two transverse rows of scales below eye larger than upper; naked flange of ventral edge of preopercle about half height of lower row of scales; base of dorsal and anal fins with a row of large elongate scales, one per membrane (except first scale which covers membranes of first and second spines), the longest about one-half spine length (basal scales progressively shorter posteriorly on membranes of soft portion of fin); peduncular lateral line scales followed by one slightly larger pored scale (included in lateral line count) on base of caudal fin with a slightly posterior scale above and below, these three scales followed by a vertical row of three large scales, the middle one overlapping the ones above and below, reaching two-thirds distance to posterior margin of fin; pectoral fins scaleless; pelvic fins with a median ventral process of two elongate scales, the more pointed posterior scale extending to tip of depressed pelvic spine spine; slender axillary scale of each pelvic fin extending about equal in length to pelvic spine.

Origin of dorsal fin above third lateral line scale; first dorsal spine 4.8 (7.1) in head; remaining dorsal spines progressively longer, the last 1.9 (18.1) in head; interspinous membranes of dorsal fin extending above spine tips, supported by the terminal cirrus projecting upward from just behind each spine tip; first to third dorsal soft rays the longest, 2.1 in head; origin of anal fin on a vertical with base of penultimate dorsal spine; first anal spine 4.5 (7.6) in head; second anal spine 3.9 (8.7) in head; third anal spine 3.4 (10.1) in head; fourth and fifth anal soft rays longest, 2.4 (14.2) in head; caudal fin lunate with protruding upper and lower lobes, its length 1.1 (30.3) in head; caudal concavity 2.4 (14.2) in head; third and fourth pectoral rays longest, 1.5 (22.9) in head; origin of pelvic fins below pectoral in base; pelvic fin length 1.5 (22.7) in head, the pelvic fin tips falling well short of anal fin origin when depressed; length of pelvic fin spine 3.0 (11.2) in head.

Colour of male holotype when fresh (Fig. 1): mainly dark brown with slight purplish hue; breast and belly with bronze hue, a diamond shaped, red-brown marking on each scale; iris bright red and pupil blackish; dorsal fin dark brown with white distal margin that gradually widens posteriorly, resulting in a broad white area around angular posteriormost portion of fin; anal fin dark brown with narrow white margin; caudal fin mainly brown including prominent upper and lower margins of fin, the posterior margin broadly white; pelvic fins dark brown; pectoral rays translucent with dark brown base.

Colour or male holotype in alcohol: after more than two years of preservation, the colour pattern is remarkably similar to that described in the previous paragraph with the exception of a tan iris and tannish lower one-third of the body.

Live colour of female from underwater field notes: overall brownish (red when illuminated with underwater torchlight) with faint longitudinal dark stripes on head and body and small dark spot on upper caudal peduncle.

Remarks

The caudal fin shape of the male serves to separate C. brunneus from nearly all other members of the genus which generally have truncate, emarginate, rhomboid, or lanceolate caudal fins. The only other species with produced fin lobes are C. lunatus Randall and Masuda (1991) from the Ryukyu Islands, southern Japan, and the Ogasawara Islands, and C. johnsoni Randall (1988) from the Marshall Islands. Males of both species have strongly lunate caudal fins, with the upper and lower rays forming filamentous extensions.

The distinctive colour patterns of the three species with lunate-shaped caudal fins are diagnostic. The male of C. johnsoni is primarily orange-red with bright red median fins. The new species appears to be most closely related to C. lunatus (Figure 2). The two species have a similar dorsal fin shape and there are remarkable similarities in the coloration of the median fins, which are dark (brown in C. brunneus and black in C. lunatus) with a broad white margin posteriorly on the dorsal and caudal fins. However, C. lunatus differs in having a broad orange-yellow zone along the sides at the level of the pectoral fins and fish from the Ryukyu Islands have a purplish coloration on the sides, which angles upward posteriorly to encompass the entire caudal peduncle. Male specimens of C. lunulatus from the Ogasawara Islands have pinkish coloration on the lower sides. Males from both the Ryukyu and Ogasawara islands differ from those of C. brunneus in having a pale yellowish band along the base of the dorsal fin and irregular diagonal red lines on the snout and postorbital portion of the head that extend onto the anterodorsal part of the body.

[FIGURE 2 OMITTED]

There is also a possible difference in the number of gill rakers on the first branchial arch. Randall and Masuda (1991) indicated a range of 14-17 gill rakers for six specimens of C. lunatus in comparison to 13 rakers for the holotype of C. brunneus. Of course, it would be desirable to count additional specimens of the latter species to verify this disparity. There is also a substantial difference in maximum size. Males of C. lunatus attain a maximum standard length of at least 84.9 mm. In comparison, the holotype of C. brunneus, measuring 43.6 mm SL, is scarcely more than half this size. Moreover, four more males of similar size were sighted at the type locality.

Several initial phase (female) individuals of C. brunneus were observed at the type locality. They were very similar in appearance to the female of C. lunatus from the Ogasawara Islands that was illustrated by Randall and Masuda (1991) and is included here as Fig. 3. Cirrhilabrus brunneus is presently known only from the type locality at north-eastern Kalimantan. However, it is likely to occur in adjacent areas, particularly the Palawan region of the Philippines, which frequently shares faunal elements with northern Borneo. The species was sighted on only one occasion despite nearly one month of diving. However, very few dives involved a habitat situation similar to that of the type locality, which was characterised by a steep slope beginning in relatively deep water. About 10 individuals, including the eventual holotype, were observed in 40 m depth on a flat to gently sloping rubble bottom along the upper edge of a vertical dropoff.

[FIGURE 3 OMITTED]

Etymology

This species is named brunneus (Latin: dusky or dark) with reference to the overall colour pattern of the holotype.

Acknowledgements

I am very grateful to The Nature Conservancy (TNC), especially Scott Stanley and Budy Wiryawan, for inviting me to participate in the Borneo Rapid Ecological Assessment. Excellent diving assistance was provided by TNC staff members Ibu Katherina, Tasrif Kartawijaya, Handoko Adi Susanto, and Irfan Yulianto. I am also grateful to Pak Witir, skipper of the TNC vessel "Ridges to Reefs" and his able assistant Tony Suhaimi. Coral specialist Emre Turak provided companionship and valuable advice throughout the survey. I also thank Suzette Stephens of TNC for logistic coordination. The manuscript was kindly reviewed by John E. Randall.

References

Allen, G. R. 2000. Description of a new wrasse (Pisces: Labridae: Cirrhilabrus) from northern Sumatra, Indonesia. aqua, Journal of Ichthyology and Aquatic Biology, 4 (2): 45-50.

Allen, G. R., J. E. Randall & B. A. Carlson. 2003. Cirrhilabrus marjorie, a new wrasse (Pisces: Labridae) from Fiji. aqua, Journal of Ichthyology and Aquatic Biology, 7 (3): 103-112.

Randall, J. E. 1988. Five new wrasses of the genera Cirrhilabrus and Paracheilinus (Perciformes: Labridae) from the Marshall Islands. Micronesica, 21: 199-226.

Randall, J. E. & H. Masuda, 1991. Two new labrid fishes of the genus Cirrhilabrus from Japan. Revue francaise d'Aquariologie, 18 (2): 53-60.

Randall, J.E. & B.H. Nagareda. 2002. Cirrhilabrus bathyphilus, a new deep-dwelling labrid fish from the Coral Sea. Cybium, 26 (2): 123-127.

Randall, J.E. & R.L. Pyle. 2001. Three new species of labrid fishes of the genus Cirrhilabrus from islands of the tropical Pacific. aqua, Journal of Ichthyology and Aquatic Biology, 4 (3): 89-98.

Senou, H. and T. Hirata. 2000. A new labrid fish, Cirrhilabrus katoi, from southern Japan. Ichthyological Research, 4 (1): 89-93.

Gerald R. Allen

Department of Aquatic Zoology, Western Australian Museum, Francis Street, Perth, WA 6000, Australia

Accepted: 09.02.2006
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Author:Allen, Gerald R.
Publication:Aqua: journal of ichthyology & aquatic biology
Geographic Code:9INDO
Date:Jan 1, 2006
Words:2863
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